For nine months out of the year, northern Colorado's Yampa River meanders through the blond sandstone formations of Dinosaur National Monument. But when the snow melts in May, it rears up and barrels to its confluence with the Green River. The last undammed tributary of the Colorado River, the Yampa's usually too low for rafting by late summer but is well worth an early-season trip. From the put-in at Deerlodge Park, the river's long, flat stretches are wonderful for swimming, and its big beach campsites are irresistible to kids. The whitewater isn't anything to sniff at, either; intermittent Class II and III rapids prepare you for the climax at Warm Springs Rapid, a Class IV pitch with a nearly river-wide hole at the bottom. After the Yampa joins the Green River about two-thirds of the way through the trip, rafters run through the Class III waves of Split Mountain Gorge.
En route, you can climb several hundred feet up to Wagonwheel Point at Harding Hole or investigate the archaeological remnants at Mantle Cave. Don Hatch Expeditions (800-342-8243) runs four- and five-day trips for $590 and $655, respectively. Kids ages 6-14 pay $370 for either trip. Adventure Bound (800-423-4668) runs four-day trips for $592 per adult, $542 for kids 18 and under.
Big, strong, and wide open, the Salmon is full of thrills but devoid of unpleasant surprises. Its class III-IV rapids are guaranteed to get some scream-action going, but its wide, inviting beaches are conveniently located next to big, safe eddies. Compared with the Middle Fork of the Salmon, the Main Fork has less technical, less dangerous rapids, making it a better choice for families with young kids.
After an easygoing first day, things get rowdier. On day two you'll enter Black Canyon, where the granite canyon walls close in on rafters just before they spill over the edge of Salmon Falls. About halfway through the six-day trip, you'll come to Big Mallard Rapid, a quarter mile of muscular Class IVwaves punctuated by a giant hole that could consume a school bus. A long, quiet stretch offers a breather before the pounding whitewater of Chittam Rapid ups the adrenaline ante again.
Canyons (888-634-2600) runs six-day trips on the Salmon for $1,100, including round-trip air transportation from Boise; kids must be age seven or older. If you get to the river on your own, the price drops to $950. Echo: The Wilderness Company (800-652-3246) runs five-day trips for $1,000 per adult (air not included) and $850 for kids 7-17.
The Colorado River enters one of its most spectacular stretches where it flows out of its namesake state and into Utah's Ruby and Horsethief canyons. From the put-in right off Interstate 70 in Loma, Colorado, the river heads into remote slickrock country that's as good as it gets outside Canyonlands or the Grand Canyon. With the exception of an occasional ranch and a railroad that parallels the entire 15-mile stretch until you get to Westwater Canyon, it is wilderness. The Ruby/Horsethief Canyon section of the river is wide and almost entirely flat. Kids can swim, try their hand at paddling, or spy great blue herons on the sandbars.
For something more dramatic, continue west through Westwater Canyon, just downstream. After a gentle first few miles, the river enters the inner gorge and a series of thumping Class III-IV rapids-most notably Skull, Funnel Falls, and Sock-it-to-me. Moki Mac River Expeditions (800-284-7280) runs three-day trips down the whole stretch for $340 per person for both kids and adults; it also runs one- and two-day trips down Westwater. During high water in spring and early summer, kids need to be at least 12 years old for the Westwater section.
The Chattooga, a Wild and Scenic River, bisects some of the finest wilderness in the South. It flows through the southernmost part of the Appalachians to form the border between South Carolina and Georgia. Families can get right into this wilderness on a daylong raft trip down Section III.
The Chattooga is a classic pool-and-drop river. It alternately plunges off five-and-six-foot-tall slabs of granite and slows up in long, glassy stretches. Just before the end of this nine-mile trip, rafters face their biggest challenge of the day-Bull Sluice Rapid, a Class IV drop. Nantahala Outdoor Center (800-232-7238) runs a one-day trip down this section ($62 weekdays, $71 weekends for both adults and kids, who must be at least ten years old).
For families who want more, there's the nearby Nantahala and French Broad rivers. The Nantahala is great for younger kids. At the end of the gentle eight-mile stretch, the pace picks up on two Class III rapids. NOC has half-day trips for $28-$29 (kids must weigh at least 60 pounds). NOC also leads several trips on the French Broad River (mostly Class II and III rapids) for ages eight and up. Trips run $33-$37 for a half day, $49-$53 for a full day.
"There was a huge grizzly bear on the sandbar," 11-year-old Mia Medak wrote of a recent trip down the Tatshenshini and Alsek rivers. "It was dancing in the rain." It's this kind of unadulterated wildness that leaves adults as wide-eyed as kids-huge glaciers, iceberg-choked lakes, an abundance of eagles and grizzly bears. The 150-mile length of river starts in the the Yukon, cuts through the glaciated heart of the St. Elias Range, and ends up in the fishing outpost of Dry Bay, Alaska. You won't encounter crashing whitewater; the Tat's rapids slide along at a controlled bounce, and things flatten out after the first day. But it's ideal for families who want to watch wildlife and tramp around on glaciers.
Canadian River Expeditions (800-898-7238) runs 12-day trips from June through August. Adults pay US$2,350; kids 19 and under get a 20 percent discount (the minimum age is eight).